feat(js): add solutions for 2024 day 19

js/src/2024/19/index.js

@@ -0,0 +1,48 @@
+import { solution } from '../../utils/index.js';
+
+const parse = (input) => {
+  const parts = input.trim().split('\n\n');
+
+  const available = parts[0].split(', ');
+  const desired = parts[1].split('\n');
+
+  return { available, desired };
+};
+
+// Calculates whether a given design is possible and returns how many variations
+const build = (design, available, cache = new Map()) => {
+  if (cache.has(design)) {
+    return cache.get(design);
+  }
+
+  let count = 0;
+  for (const pattern of available) {
+    if (design.startsWith(pattern)) {
+      const remaining = design.slice(pattern.length);
+
+      if (!remaining.length) {
+        count += 1;
+        continue;
+      }
+
+      count += build(remaining, available, cache);
+    }
+  }
+  cache.set(design, count);
+  return count;
+};
+
+export const partOne = solution((input) => {
+  const { available, desired } = parse(input);
+  return desired.reduce((sum, design) => {
+    if (build(design, available)) {
+      return sum + 1;
+    }
+    return sum;
+  }, 0);
+});
+
+export const partTwo = solution((input) => {
+  const { available, desired } = parse(input);
+  return desired.reduce((sum, design) => sum + build(design, available), 0);
+});

puzzles/2024/19/examples.yaml

@@ -0,0 +1,17 @@
+part-one:
+  - input: &example1 |
+      r, wr, b, g, bwu, rb, gb, br
+
+      brwrr
+      bggr
+      gbbr
+      rrbgbr
+      ubwu
+      bwurrg
+      brgr
+      bbrgwb
+    answer: 6
+
+part-two:
+  - input: *example1
+    answer: 16